1. Field of the Invention
The invention is directed to an energy-recuperating fluid vibration damper.
2. Detailed Description of the Prior Art
Conventional vibration dampers such as those employed in a motor vehicle operate on the principle that kinetic energy due to external excitation is converted into heat by the displacement of a damping fluid through a choke. This heat is then dissipated via the wall of the vibration damper, possibly by making use of airflow. The great advantages of this constructional principle reside in the simplicity of the vibration damper and in the many years of experience in production technology.
However, this constructional principle also entails the drawback that the generated energy is dissipated without being used. For this reason, efforts have already been made over a long period of time to make use of the energy generated by the excitation of the vibration damper. WO 2009/060296 A2 describes a vibration damper in which a fluid flow drives a hydraulic motor connected to a generator. In this way, the energy generated from the excitation is available in the form of electric current.
WO 2009/060296 A2 further discloses an emergency operation function. When the pressure in the fluid line to the hydraulic motor increases, a parallel-connected pressure limiting valve opens.
The principle of operation has the drawback that the generation of electric energy is affected just as much by large changes in the piston rod velocity. Further, no solution is presented for the problem of excessive leakage in the hydraulic motor. With leakage of this kind, fluid could be pumped between the two working chambers by movement of the piston rod virtually without choking so that there would not be sufficient damping force.